Artificial hand



Sept. 22, 1953 "iled Nov. 28, 1951 J. sARGEsoN 2,652,570

\ ARTIFICIAL HAND 4 Sheets-Sheet l INVENTDR SQP- 22, 1953 J. sARGEsoN2,652,570

ARTIFICIAL HAND Filed NOV. 28, 1951 Sheets sheet 2 Illllf INVENTUR JOHN/RGESON i9 4 Sheets-Sheet 3 N E NTD R ./oH/v SRGEsc/v EYMM M J. SARGESONARTIFICIAL HAND Sept. 22, 1953 Filed Nov. 28, 1951 SePt- 22, 1953 J.sARGEsoN 2,652,`570

\ ARTIFICIAL HAND `Filed Nov. 28, y1951 4 sheets-sheet 4 Patented Sept.22, 1953 UNITED STATES FATENT OFFICE 7 Claims.

grasp an object when the opening pressure is discontinued.

A further object of the invention is to provide a gripping device for anartificial hand comprising relatively movable jaws and an actuator forone of the jaws. The actuator includes a flexible element connecting theone jaw to a limb of the wearer, such as a leg, by means of a reel orlike device which is adapted to accommodate natural movement of the leg,and which is controlled in a manner that movement of the leg exerts apull on the flexible element for operating the one jaw. The reel iscontrolled by a ratchet mechanism which is devised to lock it by footmovement.

A still further object is to provide in an articial hand a pair ofco-acting jaws in which one of the jaws is pressed towards the other bya spring, and in which the actuator overcomes the spring pressure inorder to open the jaws for gripping an object.

Still another object is to provide a highly serviceable and efficientarticial hand comprising jaws which are relatively movable andcontrolled by an unbending movement of a leg of the wearer withouthampering ordinary use of the legs as in walking.

Still another object of the invention is to furnish an artificial handincorporating a mechanical gripping appliance which is easy tomanipulate and which assures of a uniform gripping pressure beingapplied in each operative movement.

Having recounted the major objects and advantages of the inventionsubsidiary objects and advantages will be apparent from the ensuingspeciiication of which the accompanying drawings form a part.

In the drawings,

Fig. l is a side view of the artificial hand showing how it is worn andconnected to a leg of the wearer for operation of the gripping device;

Fig. 2 is a similar view, but depicting how the gripping device takeshold of an object;

Fig. 3 is a side view, partly in section, of the artificial hand inwhich the movable jaw is depicted in its second position in dash lines;

Fig. 4 is a further side View of the artificial hand, but taken at rightangles to Fig. 3;

Fig. 5 is a side view of the actuator which is mounted on the leg of thewearer to control the movable jaw;

Fig. 6 is a side view partly in section of the ratchet controlled reel;

Fig. 7 is a section on line 1-1 of Fig. 6 depicting the winding springfor the reel;

Fig. 8 is a view in perspective of the reel support which is applied toa foot of the wearer. In this View the attachment strap is showndetached from the stirrup element;

Fig. 9 is a section on line 9-9 of Fig. 3;

Fig. 10 is a side view of the jaws showing more clearly the arrangementof the iiexible elements by which the movable jaw is controlled; and

Fig. 11 is a diagrammatic detail showing the means for adjusting thetension of the spring for closing the jaws.

In carrying out my invention there is provided a socket as usual forattachment to the amputated limb. The socket may be of conventionalconstruction according to the nature of the amputation, but desirably Iconstruct the socket with a major part of a rigid material, and with theremaining part of a iexible material. Said major part forms the bodyportion I4 of the socket and comprises a rigid wall which substantiallysurrounds the amputated limb but leaves an opening at one side thereofwhich is closed by the flexible element, denoted at l5. The flexibleelement is secured along one of its longitudinal edges to the bodyportion I4. Adjustable fastening means are provided at the otherlongitudinal edge to enable the socket to be bound firmly on theamputated limb. Suitable fastening means may consist of the tags I6 andthe lace Il, but other fastening means may be substituted if so desired.

To assist in the secure attachment of the appliance and to prevent itfrom becoming askew, the upper end of the socket is supplied with astrap i8 which is adapted to encircle the arm of the wearer at a pointslightly above the elbow. The strap is adjustable by means of the buckleI9 and is joined to the body portion lli by the lateral connecting parts20.

The hand or grasping portion of the appliance is carried as usual by thesocket and comprises a gripping device. Said gripping device is of anovel construction and comprises a pair of coacting jaws supported foropening and closing movements. Jaw 2| is iiXed on a support 22 to extendoutwardly of the bottom end 23 of the socket. The other jaw, indicatedat 2li, is movable on the support 22 as by the pivotal connection 25 andnormally is held in a closed position alongside of the jaw 2| by springpressure.

Preferably the closing pressure is applied to the movable jaw by ahelical tension spring 26 having an end connected to the body |4 of thesocket, the other end being attached to a flexible element 21 in theform of a nylon cord which is arranged to exert a closing force on themovable jaw under tension of the spring 26. Said cord extends from plate28 on the free end of this spring and is engaged with a grooved roller29 in the movable jaw 24 and is similarly engaged with a grooved roller30 in the xed jaw 2| from where it extends to the support 22 and isanchored thereto by its end part 3|. 'With this arrangement the cord 21translates the spring tension into a smooth and strong closing force onthe movable jaw.

The closing force on the movable jaw can be adjusted by any suitableexpedient. One way of achieving this is to provide a plurality of spacedknobs or nodules 32 on the end 3| of the cord 21 and to selectivelyengage one of these with a bifurcated anchor plate 33 on the support 22.The arrangement enables the tension of the spring 26 to be increased ordecreased according to requirements in the use of the appliance. Theadjustment is comparatively coarse, therefore a liner adjustment may beincorporated in the structure if so desired. This may comprise a headedscrew 34 carried by the socket and threadedly engaged in an internallythreaded plug 35 secured to the fixed end of the spring 26. The screw 34is rotatably mounted on the socket by means of the bracket 36 and isshouldered thereon by its head so that it can turn freely. It will beunderstood that a ne adjustment of the spring tension can be had byturning the screw relative to the plug, The tensioning means for themovable jaw along with the adjustment means therefor will be bestunderstood from an inspection of Figs, l and 11.

The gripping faces 31 and 38 of the jaws may be made of hard or softmaterial to best suit the objects to be held. Rubber can be used as asoft facing material Where there is a likelihood of defacing articles tobe grasped. Furthermore, one of the jaws may be equipped with aself-aligning jaw-piece 39 which is pivoted at 49. Modification in thisrespect may be resorted to within the scope of the invention. It mayalso be desirable to mount the jaws on the socket in a manner to permitthem to be turned to different angular positions. This can beaccomplished by pivoting the support 22 at as 4| (Fig. 3) and providinga latching device for retaining it in a set position. Such a latchingdevice may consist of a circular series of holes 42 in the end wall 23of the socket and a latching bar 43 on the support 22. The latching baris spring pressed in order to be selectively engaged in one or anotherof the holes 42.

It will be understood from the preceding description that the movablejaw is normally retained in closed position by the pressure of thetension spring 26 and that in order to open the jaws it is necessary torelieve the movable jaw of the pressure of the spring. The actuating`device serves this purpose and comprises a flexible cable 44 freelyextending through a flexible tube 45, which are similar to thewell-known Bowden wire. One end of the cable 44 is secured to a nyloncord 46 which is engaged with a grooved roller 41 on the support 22 andconnected to the spring 26 so that when pulled it will act to stretchthe spring. It is preferable to increase the purchase by providing agrooved roller 48 on the plate 28 and engaging the cord 46 with thisroller and securing the free end 49 of the cord to the support 22.

The cable 44 and the tube 45 are extended over the near shoulder of thewearer and down the back in order to reach to the leg of the wearerremote from the arm on which the artificial hand is used. On this legthere is `applied the pulling device by which a pull can be exerted onthe -cable by means of a straightening movement of the leg after it hasbeen bent. The pulling device comprises a Winding reel 50 fastened onthe leg below the knee. The reel is mounted on a support in the form ofa case 5| which is secured to a pliant band 52. Said band is a splitmember of soft leather or other suitable material adapted vto encirclethe leg and be fastened thereon by conventional means, such as anadjustable fastener indicated at 53. A shoulder pad 54 is attached tothe iiexible tube 45.

The cable has an end 55 secured to the reel 50 and wound thereon underthe influence of a coil spring 56. The major part of the cable may bemade of readily flexible wire, whereas the end part 55 may consist of anylon cord which is capable of more readily winding on the reel. Thespring 56 is suitably tensioned to exert a Winding force on the reel,which spring is a spiral member having its outer end secured to the reeland having its inner end secured to a stationary shaft 51.

The reel is tensioned sufliciently to take up slack in the cable and topay it out as required in any movement of the leg, such as in walking.From the preceding description it will be manifest that a fairly strongpull must be exerted to stretch the spring 26 in order to open themovable jaw 24. The reel spring 56 is not of sumcient strength for thispurpose, but merely functions to keep the cable taut at all times. Thereel, by paying out the cable and reeling it in, permits unhamperedmovement of the leg to which it is attached. Also it does not restrictmovement of the arm to which the appliance is attached.

When it is desired to open the jaws the reel is prevented from turningin an unwinding movement so that the leg to which it is attached may beilexed and then straightened to exert a pull on the cable. In theflexing movement of the leg the reel turns under the spring pressure toWind up the slack of the cable incidental to the flexing action. Thereel is then stopped against unwinding by a ratchet device hereinafterdescribed. In this way a pull of considerable force can easily beapplied to the cable by the unbending of the leg at the knee, whichopens the 'movable jaw to the desired extent. The straightening of theleg enables the spring 26 to vclose the jaw.

The ratchet device comprises the provision oi one way teeth 51 on aflange portion of the reel. A peripheral series of the teeth are usedand the structure constitutes a ratchet wheel embodied in the reel. Apawl 58 co-acts with the ratchet teeth 51 and is pivoted at 58' on thesupport 5| intermediate of its length. One end of the pawl is arrangedto swing into engagement with a ratchet tooth when the other end ispulled downwardly. The ratchet teeth and the pawl operate to prevent thereel from turning in an unwinding direction. The pawl is normallyretained in a disengaged position (Fig. 6) as by the coil spring 59.

A flexible element, such as a cord 60 is employed to actuate the pawlfor causing it to engage the ratchet wheel. This cord is connected tothe forepart of the foot and is of such a length that the foot can exerta pulling force by merely bending the foot downwardly at the ankle, asclearly represented in dash lines in Fig. 5. The cord is detachablyconnected to the shoe on the foot in any convenient manner.

In order to prevent displacement of the reel in an operational movement,it is desirable to employ a stirrup 6I by which the pulling force of thecable is taken on the foot portion of the leg on which the actuatingdevice is worn. The stirrup is shown as a U-shaped member, which may bemade up of wire rod material and has its bight portion disposed underthe arch of the foot, the end parts '62 being pivoted or otherwiseattached to the band 52. Said stirrup is shown as fastened to the footby a flexible strap E3 of an adjustable character, which extends overthe instep and has its end parts hooked onto the stirrup near the bightportion thereof.

From the preceding description it will be manifest that my inventionsupplies an eflicient and easily manipulated artificial hand of whichthe jaws are capable of firmly grasping various kinds of objects. In theuse of the appliance the spring 26 retains the movable jaw 24 in closedposition. To open this jaw the wearer bends at the knee the leg to whichthe actuating device is applied-see Fig. l. In the bending movement thecable winds on the reel and is maintained in a taut condition. He thenbends the foot of this leg downwardly at the ankle to cause the pawl 58to engage a ratchet tooth 55 to lock the reel against unwinding. The legis then straightened, which pulls on the cable and relieves the movablejaw of the pressure of the spring 26. A comparatively light spring 63(Fig. 3) is used to open the movable jaw. To close this jaw the foot isbent upwardly at the ankle to its former position to slacken the cord 60and allow the spring 59 to disengage the pawl 58. This permits the reelto turn in an unwinding direction so as to permit the spring 26 to applyclosing pressure on the movable jaw for grasping an object.

It is of course evident that when the wearer puts the apparatus on thebody (each day, presumably) there will be an initial operation ofadjusting the cable and reel to preset the amount of slack or tension inthe cable to a predetermined desirable condition: this may requireseveral kick-like movements of the limb to wind the reel until thespring tension 26 comes into its normal rest valve. Thereafter it isnecessary to operate the actuating limb through only one cycle as abovedescribed in order to operate the grasping jaws. The nodules 32 andadjusting means shown in Fig. 11 ensure that the presetting operation isconfined within conveniently narrow limits, at the same time providingsome allowance for changes which may occur from time to time in bodydimensions, or to ageing of tensed parts of the apparatus.

What I claim is:

l. In an articial hand, a socket, a gripping device carried therebyincluding a jaw pivoted to swing from closed to open position, a rolleron said jaw remote from the pivotal axis thereof, a helical tensionspring anchored at an end on said socket, a cord connected to the otherend of said spring and engaged on said roller and fastened to saidsocket with said spring under tension, the tension of said springretaining said jaw in closed position, a flexible element connected tosaid jaw for effecting an opening movement thereof when pulled, atensioned reel for attachment to a limb of the wearer and connected tosaid flexible element for winding and unwinding movements, means forlocking said reel against turning in an unwinding direction and in whichthe cord is provided with a plurality of spaced nodules at an endthereof for selective engagement with a bifurcated member on the socketwhereby to fasten the cord in an adjustable manner to vary the tensionof the spring.

2. In an artificial hand, a socket, a gripping device carried therebyincluding a movable jaw spring pressed to closed position, and means foropening said jaw, said means comprising a flexible element having aconnection with said jaw for overcoming the pressure thereon whenpulled, a spring tensioned reel operative to wind said iiexible elementto maintain it in a taut condition, means for strapping said reel on a,limb of the wearer, and a ratchet device for holding the reel againstunwinding.

3. In an artificial hand, a socket, a gripping device carried therebyincluding a movable jaw spring pressed to closed position, and means foropening said jaw, said means comprising a flexible element having aconnection with said jaw for overcoming the pressure thereon whenpulled, a spring tensioned reel operative to wind said flexible elementto maintain it in a taut condition, a band supporting said reel andadapted for attachment to a limb of the wearer, ratchet teeth on saidreel, a pawl supported on said band for engaging said ratchet teeth, andmeans for operating said pawl.

4. A structure as set forth in claim 3, in which the means for operatingsaid pawl comprises a spring pressing said pawl away from said ratchetteeth, and a cord connected to said pawl for attachment to a relativelybendable part of said limb.

5. In an artificial hand having a movable jaw. a mechanism for actuatingsaid jaw comprising a ilexible element connected to said jaw, a springtensioned reel connected to said flexible element for taking up slacktherein, a case housing said reel, a pliant band on which said case ismounted, said band being constructed for attachment to a limb of thewearer, means providing ratchet teeth on said reel, a pawl for engagingsaid ratchet teeth, a spring acting to press said pawl away from saidratchet teeth, and a cord attached to said pawl for moving it intoengagement with said ratchet teeth.

6. A limb simulating apparatus comprising a socket, a gripping devicecarried thereby and including a movable jaw and a spring urging said jawtoward a predetermined position with respect to a mating jaw, and meansfor altering the said predetermined position against the urge of saidspring, said means being characterized by a ilexi'ble element having aconnection with said movable jaw for overcoming the pressure thereonwhen pulled, a spring tensioned reel operative to wind said flexibleelement to maintain it in a taut condition, a ratchet device capable ofholding the reel against unwinding and means associated with a selectedlimb member for latching and unlatching the said reel.

7. In an articial hand, a jaw supporting 7 socket, fa jam/'mountedthereon for movement be- References Cited lin the me of this tweenclosed and :open positions, resilient means UNITED STATES P normaihfretaining said jaw i-n -a closed position,

a. spring supported to act on 'said jaw to press it Number. 4 Naim@ Dm,

2532 732 Sansbur Dec 5 1950 to 0. n, t n, exlbl elem nt tt ched to I f yi De posi 1 a e e a a 2,537,551 sansbury -..v,-. Jan. 9, 1951 andextend-ing from s'a/id jaw, ra, tensioned reel for attachment to a,111mb of 'the wearer and connected to said flexible element for windingvand unwinding movements, a means for locking said reel against turningin an unwindng direction. 10

JOHN SARGESON.

